Ministers will close the door to Bulgarians and Romanians hoping to live and work in Britain today as the government tries to deflect criticism that it has lost control of the immigration system. The move, which maintains the tight controls introduced last year, means they are still being refused the rights given to migrants from six other eastern European accession countries.

The Foreign Office has raised protests in Whitehall, but pressure to act has been driven by the scale of recent migration projections and concern that the issue is a big negative factor for Labour in its private polling. The government's advisory Migration Impacts Forum told ministers this month that immigration is now seen as the number one issue facing Britain.

The government hopes to neutralise the issue in the new year with the introduction of an Australian-style points system for migrants who want work in key sectors of the economy hit by labour shortages.

Ministers were forced to reveal yesterday that they had revised figures for the increase in the number of foreign nationals working in the UK since 1997 from 800,000 to 1.1 million.

Foreign nationals now account for between 7% and 8% of the 29.1 million people in work in the UK.

Peter Hain, the work and pensions secretary, had to apologise last night after the government revised its figure. He has written to Chris Grayling, his Tory shadow, to apologise for incorrect figures given in response to questions in the Commons and parliamentary written answers. "I apologise for having to make this revision," Mr Hain wrote, adding that the new figure was the most "robust estimate available".

Mr Grayling called the admission "an extraordinary development". He said: "The fact that the government did not know the true number of overseas workers who have come to the UK in the past 10 years is profoundly worrying, and confirms fears that ministers have simply lost control of our systems for migrant workers."

Yesterday David Cameron waded into the debate with his first big speech on immigration roundly criticising the government, which is bracing for further attacks on its policies this week.

· On Thursday the Local Government Association will criticise the government for failing to fund councils put under pressure by migration inflows. It will claim ministers have no reliable system of funding the costs of servicing migrants and still have no accurate means of measuring where migration is taking place in Britain. Research commissioned for the LGA will claim the care of unaccompanied asylum-seeking children in a single London borough now costs £4.7m a year.

· In evidence to a Lords committee, the Statistics Commission, the government's watchdog, has also warned that "weak data on migration can lead to inefficiency in the allocation of grants to local authorities, the NHS and other public services." It went on: "Some £100bn a year is being distributed through formulae that are directly affected by migration estimates. We are not in a position to estimate the cost to the public purse ... but it could be very substantial." The commission has also claimed the government is indefensibly failing to cooperate with the Office of National Statistics and not funding the work needed to make Britain's migration statistics accurate.

In his set-piece speech yesterday Mr Cameron promised to set an annual cap on the number of migrants entering Britain from outside the EU. It would be set significantly lower than the current net migration figure of 200,000, he said.

The immigration minister, Liam Byrne, conceded that the pace of change was unsettling some communities. But he attacked the idea of an annual cap as ineffective and dismissed the "talk of a cap on numbers, when you can't, or won't, name a number" as a smokescreen for Mr Cameron's "lack of new, credible thinking, especially when the small print reveals his cap appears not to touch EU nationals, overseas students and dependents - groups who made up the vast majority of Britain's incomers last year".

Mr Byrne is planning to set his own version of a cap through a points-based system next January that will set out the number of workers required in specific industries each year. In internal Home Office papers he has described the system as a flexible threshold that migrants from outside the EU must cross to come to Britain, adding that the level could be moved quickly depending on the UK's needs.